hi asterix! learning to read greek on paper, and learning to speak greek using the accents, are 2 different skills: if you want to learn both, you should choose to start learning/reading a text where (a) someone has given grammatical information about each word of the text, and (b) someone has put an audio recording online using a reconstructed pitch pronunciation.

hi asterix, ancient greek, like modern japanese, was a pitch language: each syllable in a word has a certain pitch/tone. it's still unclear whether certain syllables were stressed as well. so basically greek sentences go up and down in pitch, unlike english which has patterns of strongly- and weakly-emphasised syllables, based on the proper stress of the syllables in the words.

the little accent signs above greek letters, which look like the french accents, tell you roughly how to pronounce the pitch/tones of the word.

the acute accent means that the syllable underneath it has the highest pitch: it's the accent peak of the word. the circumflex means that the syllable underneath it hits 2 different pitches: first, the highest pitch, then, a lower pitch. the grave accent is quite complicated...

the best way to learn how these work is to imitate the reconstructed pronunciations online. the problem with that is that you don't know how much of the recording is accurate "reconstruction" and how much of it is the natural timbre and quality of the person's own natural voice.

to avoid this i've tried to phonetically and graphically represent the proper pronunciation of greek. if you go to this temporary website

and go to the "sappho" file (a work-in-progress which i just uploaded a few minutes ago for you... i've only put on the first few pages...), you'll see that i've mapped out each syllable of the line: they go up and down with the pitch accents. some things to note in the .pdf:

* a ~ sign means that you sustain the previous syllable for an extra beat (because some syllables in greek are long, and some are short)
* ignore the shaded columns (they're in there to show when an anceps syllable is short)
* ignore the grey capital letters underneath each line (they're my own annotations for mapping out the pitch: they refer to my pitch modelling document on the same website)

if you can work out what i've done, it might answer some of your questions... if you've got any more questions i'll be happy to answer them here...